upload android base code part3

android/dalvik/libdex/Leb128.h

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+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/*
+ * Functions for interpreting LEB128 (little endian base 128) values
+ */
+
+#ifndef LIBDEX_LEB128_H_
+#define LIBDEX_LEB128_H_
+
+#include "DexFile.h"
+
+/*
+ * Reads an unsigned LEB128 value, updating the given pointer to point
+ * just past the end of the read value. This function tolerates
+ * non-zero high-order bits in the fifth encoded byte.
+ */
+DEX_INLINE int readUnsignedLeb128(const u1** pStream) {
+    const u1* ptr = *pStream;
+    int result = *(ptr++);
+
+    if (result > 0x7f) {
+        int cur = *(ptr++);
+        result = (result & 0x7f) | ((cur & 0x7f) << 7);
+        if (cur > 0x7f) {
+            cur = *(ptr++);
+            result |= (cur & 0x7f) << 14;
+            if (cur > 0x7f) {
+                cur = *(ptr++);
+                result |= (cur & 0x7f) << 21;
+                if (cur > 0x7f) {
+                    /*
+                     * Note: We don't check to see if cur is out of
+                     * range here, meaning we tolerate garbage in the
+                     * high four-order bits.
+                     */
+                    cur = *(ptr++);
+                    result |= cur << 28;
+                }
+            }
+        }
+    }
+
+    *pStream = ptr;
+    return result;
+}
+
+/*
+ * Reads a signed LEB128 value, updating the given pointer to point
+ * just past the end of the read value. This function tolerates
+ * non-zero high-order bits in the fifth encoded byte.
+ */
+DEX_INLINE int readSignedLeb128(const u1** pStream) {
+    const u1* ptr = *pStream;
+    int result = *(ptr++);
+
+    if (result <= 0x7f) {
+        result = (result << 25) >> 25;
+    } else {
+        int cur = *(ptr++);
+        result = (result & 0x7f) | ((cur & 0x7f) << 7);
+        if (cur <= 0x7f) {
+            result = (result << 18) >> 18;
+        } else {
+            cur = *(ptr++);
+            result |= (cur & 0x7f) << 14;
+            if (cur <= 0x7f) {
+                result = (result << 11) >> 11;
+            } else {
+                cur = *(ptr++);
+                result |= (cur & 0x7f) << 21;
+                if (cur <= 0x7f) {
+                    result = (result << 4) >> 4;
+                } else {
+                    /*
+                     * Note: We don't check to see if cur is out of
+                     * range here, meaning we tolerate garbage in the
+                     * high four-order bits.
+                     */
+                    cur = *(ptr++);
+                    result |= cur << 28;
+                }
+            }
+        }
+    }
+
+    *pStream = ptr;
+    return result;
+}
+
+/*
+ * Reads an unsigned LEB128 value, updating the given pointer to point
+ * just past the end of the read value and also indicating whether the
+ * value was syntactically valid. The only syntactically *invalid*
+ * values are ones that are five bytes long where the final byte has
+ * any but the low-order four bits set. Additionally, if the limit is
+ * passed as non-NULL and bytes would need to be read past the limit,
+ * then the read is considered invalid.
+ */
+int readAndVerifyUnsignedLeb128(const u1** pStream, const u1* limit,
+        bool* okay);
+
+/*
+ * Reads a signed LEB128 value, updating the given pointer to point
+ * just past the end of the read value and also indicating whether the
+ * value was syntactically valid. The only syntactically *invalid*
+ * values are ones that are five bytes long where the final byte has
+ * any but the low-order four bits set. Additionally, if the limit is
+ * passed as non-NULL and bytes would need to be read past the limit,
+ * then the read is considered invalid.
+ */
+int readAndVerifySignedLeb128(const u1** pStream, const u1* limit, bool* okay);
+
+
+/*
+ * Writes a 32-bit value in unsigned ULEB128 format.
+ *
+ * Returns the updated pointer.
+ */
+DEX_INLINE u1* writeUnsignedLeb128(u1* ptr, u4 data)
+{
+    while (true) {
+        u1 out = data & 0x7f;
+        if (out != data) {
+            *ptr++ = out | 0x80;
+            data >>= 7;
+        } else {
+            *ptr++ = out;
+            break;
+        }
+    }
+
+    return ptr;
+}
+
+/*
+ * Returns the number of bytes needed to encode "val" in ULEB128 form.
+ */
+DEX_INLINE int unsignedLeb128Size(u4 data)
+{
+    int count = 0;
+
+    do {
+        data >>= 7;
+        count++;
+    } while (data != 0);
+
+    return count;
+}
+
+#endif